汽轮机高压调节汽门阀杆断裂原因分析

Cause Analysis on Valve Stem Rupture Failure of Steam Turbine HP Control Valve

针对某火厂C300/220-16.67/537/537型汽轮机高压调节汽门阀杆的断裂情况,通过宏观检查、化学成分分析、金相分析和机械性能分析等常规检查,排除了阀杆材质和性能因素的影响。从阀杆的结构和阀杆在工作中的受力情况判断,阀杆断裂是螺纹根部加工尖角严重导致的应力集中、在变工况下运行形成的长期低频振动、阀杆套与阀杆之间间隙的增大和螺纹根部表面的氮化处理等共同作用的结果,并针对阀杆断裂的原因提出了针对性的建议。

In view of the rupture of C300/220-16.67/537/537 type turbine high pressure control valve stem in some power plant, the study eliminated the material quality and characteristics of valve stem rupture, through macroscopical inspection, chemical component analysis, metallography analysis, and engine performance analysis. The reasons were effeeted by stress focus of screw thread end needle corner, long period low frequency vibration during changeable operation state, clearance increasing between valve stem cover and valve stem,and nitrification treat on the screw thread end exterior, from analysis on valve stem structure and forced condition during valve stem operation. The author points out the perti nence suggestions to equipment trouble and to avoid acci dent.